Experimental Investigation of the Minimum Oil-Film Thickness in Spur Gears

1963 ◽  
Vol 85 (3) ◽  
pp. 451-455 ◽  
Author(s):  
D. W. Dareing ◽  
E. I. Radzimovsky
Keyword(s):  
Film Thickness ◽  
Voltage Drop ◽  
Planetary Gear ◽  
Gear Train ◽  
Spur Gears ◽  
Minimum Thickness ◽  
Testing Technique ◽  
Oil Film ◽  
Gear Teeth ◽  
Gear Drive

As a pair of gears is loaded, the minimum oil-film thickness between the gear teeth decreases and can approach a magnitude equal to the magnitude of the surface roughness. Metal-to-metal contact then occurs between the microscopic peaks on both mating teeth surfaces. Therefore, the minimum thickness of the film separating the mating teeth surfaces may be considered as one of the criteria of capacity for a gear drive. A testing technique that was developed for measuring oil-film thickness between loaded gear teeth while running is presented in this paper. The voltage drop across a thin oil film that is required to cause an electrical discharge was used to determine the oil-film thickness. A specially designed machine containing a planetary gear train was used in these experiments. The relationships between the minimum oil-film thickness and the load transmitted by the gearing under certain conditions were determined using this method.

The Measurement of Oil-Film Thickness in Gear Teeth

1960 ◽  
Vol 82 (1) ◽  
pp. 29-34 ◽  
Author(s):  
I. O. MacConochie ◽  
A. Cameron
Keyword(s):  
Film Thickness ◽  
Voltage Drop ◽  
Theoretical Work ◽  
Discharge Voltage ◽  
Constant Current ◽  
Oil Film ◽  
Gear Teeth ◽  
Order Of Magnitude ◽  
The Difference ◽  
Experimental Values

The voltage drop across thin oil films when a constant current of 1 amp is passed, i.e., the discharge voltage, is used to measure the oil-film thickness between loaded gear teeth while running. It is found that the thickness at the pitch line is between 1 and 4 × 10−4 in., which varies slightly with the viscosity and rather more strongly with load. The thickness at the tips and roots is very dependent on the tip relief. The conditions here may explain the difference between disk and gear tests. These experimental values are compared with theoretical work and are shown to be of the same order of magnitude.

Contact Analysis of Gear Trains Using Linear Complementarity Based Compliant Contact Model

2019 ◽  
Author(s):  
Mangesh Pathak ◽  
Sourav Rakshit
Keyword(s):  
Finite Element ◽  
Computation Time ◽  
Planetary Gear ◽  
Element Model ◽  
Linear Complementarity ◽  
Contact Analysis ◽  
Contact Forces ◽  
Gear Train ◽  
Spur Gears ◽  
Gear Contact

Abstract The current computation models for gear contact analysis and wear prediction are mostly based on finite element analysis which consumes much computation time and effort. In this work, we adopt an alternative approach for gear contact analysis using linear complementarity. This approach was successfully applied to a pair of rigid spur gears and a planetary gear train (gears are considered as rigid bodies) in our previous work. In this paper, we extend our linear complementarity model to consider local deformation caused due to contact between gear teeth in mesh. Thus obtained linear complementarity model is applied to a pair of spur gears and a planetary gear train. A linear complementarity solver computes the contact forces between meshing teeth of gears. From the contact forces, sliding wear in gear teeth is predicted. Archard’s wear model is used for the wear prediction. Using this model, the contact forces are uniquely determined for the examples considered. The results of linear complementarity and finite element model for a pair of spur gears are compared. The linear complementarity model consumes much less computation time than the finite element model.

Simplified modellization of gear micropitting

2002 ◽  
Vol 216 (6) ◽  
pp. 291-302 ◽  
Author(s):  
F Antoine ◽  
J-M Besson
Keyword(s):  
Film Thickness ◽  
Thermochemical Treatment ◽  
Gear Train ◽  
Surface Finishing ◽  
Case Hardening ◽  
Reference Case ◽  
Oil Film ◽  
Epicyclic Gear ◽  
Wide Range ◽  
Physical Phenomena

This document gives a simplified method of calculating gear micropitting. The method has been developed by EUROCOPTER. The objective was to provide a model that took into consideration the maximum number of parameters in order to model the different physical phenomena, particularly: an oil-film thickness calculation taking the influence of pressure into consideration a simplified modellization of roughness an estimation of the plastification effect on the roughness overpressure at the contact surface taking into account the combined effects of roughness and oil-film thickness. The elaborated model is presented in an Excel file form. The application program is called APICS (approche du pitting par calculs simplifiés). In order to validate this model, this program has been applied to: An epicyclic gear train of a helicopter. Tests on discs as part of the ASETT European program. Discs are in hardened M50NiL Duplex (surface treatment: carburized and nitrided). Different kinds of surface finishing were proposed. The reference case of discs in 16NCD13 without thermochemical treatment has been also treated. FZG gear benchtests, also as part of the ASETT program. Gears have been manufactured in hardened M50NiL Duplex, with different kinds of surface finishing proposed. The results of the calculations express quite exactly the experimental facts observed on discs and gears for a wide range of studied cases, covering different materials, different kinds of case hardening and different kinds of surface finishing.

scholarly journals Stress Assessment of Gear Teeth in Epicyclic Gear Train for Radial Sedimentation Tank

2020 ◽  
Vol 14 (3) ◽  
pp. 121-127
Author(s):  
Grzegorz Budzik ◽  
Tadeusz Markowski ◽  
Michał Batsch ◽  
Jadwiga Pisula ◽  
Jacek Pacana ◽  
...  
Keyword(s):  
Planetary Gear ◽  
Gear Train ◽  
Load Factor ◽  
The Finite Element Method ◽  
Gear Teeth ◽  
Gear Mesh ◽  
Sedimentation Tank ◽  
Epicyclic Gear ◽  
Comparison Of The Results ◽  
Root Stress

Abstract The paper presents the strength evaluation of planetary gear teeth designed for a radial sedimentation tank drive. A novel type of gear drive, composed of a closed epicyclic gear train and an open gear train with internal cycloidal gear mesh is proposed. Contact stress and root stress in the planetary gear train were determined by the finite element method and according to ISO 6336. The influence of the mesh load factor at planet gears on stress values was also established. A comparison of the results followed. It was observed that the mesh load factor on satellites depends mainly on the way the satellites and central wheels are mounted, the positioning accuracy in the carrier and the accuracy of teeth. Subsequently, a material was selected for the particular design of planetary gear and the assumed load. The analysis of the obtained results allowed assuming that in case of gears in class 7 and the rigid mounting of satellites and central wheels, gears should be made of steel for carburizing and hardening. In case of flexible satellites or flexible couplings in the central wheels and gears in class 4, gears can be made of nitriding steel.

Measurement of Oil Film Thickness Between W-N Helical Gear Tooth Profiles Using Laser Transmission Method

1990 ◽  
Vol 112 (4) ◽  
pp. 708-711 ◽  
Author(s):  
Yang Ji-Bin ◽  
Qi Yu-Lin ◽  
Chen Chen-Wen
Keyword(s):  
Film Thickness ◽  
Gear Tooth ◽  
Helical Gear ◽  
Spur Gears ◽  
Measuring Apparatus ◽  
Transmission Method ◽  
Helical Gears ◽  
Oil Film ◽  
Measurement Results ◽  
First Time

In this experiment, it was the first time that the center oil film thickness between W-N helical gear tooth profiles has been measured indirectly through measuring the change of gaps of a pair of unloaded involute spur gears mounted on the extended shafts of W-N gear box by means of laser transmission method. During the measurement of every time, it was calibrated separately, so that all errors could be eliminated completely except ones of measuring apparatus. The accuracy of this method has reached 0.1 μm (dynamic) and 0.01 μm (static), respectively. Measurement results were identical with theoretical ones. This method is also suitable for the measurement of center oil film thickness between tooth profiles and deformation of any cylindrical spur and helical gears.

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